Alternating-current transformer.



G. LE G. FORTESCUE.

ALTERNATING CURRENT TRANSFORMER.

APPLICATION FILED 0017. s, 1910. RENEWED MAY 27, 1914.

Patented Feb. 23, 1915.

a 2 gig jJQIVENTOR ATTORNEY UNITED STATES PATENT OFFICE.

CHARLES LE GEYT ronrnscun, or rmsnuneri, rnnnsri'vnnia, ASSIGNOR 'roWEST- INGHOUSE ELECTRIC AND unmirncrunma comm, A CORPORATION orPENNSYLVANIA. I

ALTERNATING-CURRENT TRANSFOIB IMER.

To all whom it may concern Be it known that 1, CHARLES LE G. Fon-TESCUE, a subject of the King of Great Britain, and a resident ofPittsburgh, in the county of Allegheny and State of Pennsylvania, haveinventeda new and useful Improvement in Alternating-CurrentTransformers, of which the following is a specification, thisapplication being a dlvision of application Serial No. 510,854, filedAugust My invention-relates to the windings and insulation oftransformers which'are adapted for use with very high-voltage circuitsand it has for its object to provide a winding which is so connected,and insulation which is so constructed and associated with the winding,that the manufacturing cost of thetransformer and the space occupied byit may be materially reduced, while, at the same time, its terminalvoltage may be very high.

The single figure of the accompanying drawing is a sectional elevationof a trans former core and a winding arranged in accordance with myinvention.

Referring to the drawing, the structure here shown comprises asubstantially rectangular core 1, a low-potential winding 2 that isdivided into two groups of coils which surround two opposite legs 3 and4: of the core 1 and are separated therefrom by insulating sleeves 5, aprimary winding composed of two groups 6 and 7 of relatively flat coilsand insulating sleeves 8 and 9 located on the respective core legs,between the low and high-potential windings. The core legs 3 and 4 maybe of any suitable form but are preferably cruciform in crosssection, inorder to economize space and to reduce the mean length of turn in thecoils.

In my copending application, Serial No.

series to the high-potential terminal of the transformer, certainof theconnections be- Specifl cation of Letters Patent.

Original application filed August 2, 1909, Serial No. 510,854. Dividedand this application flied October 8, I 1 1910, Serial No. 586,100.Renewed May 27,1914. Serial No.

tween coils being effected by means of con-- ducting plates which formparts of the inproper distribution of stress in the insulation withoutthe use of separate conducting plates or other auxiliary means. Thecoils, which form parts. of the insulating sleeves, are composed of aplurality of layers 11 each containing a substantially equal number ofthe turns 10. The turns in the high-voltage layers which are farthestfrom the core legs are disposed side by side, and the turns of the otherlayers, from the outer ones inwardly, are spaced farther and fartherapart, being quite widely separated in the inner layers nearest to thecore legs. By this means, the potential is properly distributed throughthe insulating bushings and the layers near the core legs are asefficiently utilized as those near the high-voltage coils.

The intensity of the strain on each layer of insulation and thedistribution of stress therein is predetermined, since the potential ofeach point of the winding is fixed.

Iv claim as my invention:

1. In electrical apparatus, the combina tion with a low-potential body,and a relatively high-potential conductor, of an insulating structuredisposed between said body and said conductor and comprising a pluralityof concentric insulating cylinders and means constituting apart of theconductor for determining distribution of stress in the insulation.

2. In a transformer, the combination with a magnetizable core, and awinding therefor having a plurality of coils arranged end to end, of aninsulating sleeve disposed between said core and said winding andcomprising a plurality of layers and a series of convolutions ofelectric conductor distributed between the layers, the convolutions ofeach layer being included electrically between pairs of the coils.

3. In electrical apparatus, the combination with a low-potential bodyand a relatively high-potential conductor, of an insulating structuredisposed between sald body and said conductor and embodying meansconstituting a art of the conductor for determiningthe distribution ofstress in the insulation.

4. In an electrical device, the combination with a core, and aninsulating sleevefi surrounding the core, of a winding comprising aplurality of coils embedded in, and separated by, the insulating sleeve,the end convolutions of the coils being adjacent to the ends of thesleeve.

'5. In an electrical device, the combination with a core, and aninsulating sleeve surrounding the core, of a winding comprising aplurality of substantially concentric coils embedded in, and separatedby, the insulating sleeve, the end convolutions of the coils beingadjacent to the ends of the sleeve and the convolutions of the innercoils being speiced farther apart than those of the outer cm s.

6. In an electrical device, the combination with arcore, and aninsulating sleeve that surrounds the core and is tapered from anintermediate point toward its ends, of a insulating sleeve, the endconvolutions of the coils being adjacent to the ends of the steps in thesleeve. 4

8. In an electrical device, the combination with a core, and aninsulating structure surrounding the core having stepped ends, of

a winding comprising a plurality of coils separated by the insulatingstructure, the

end convolutions of the coils being adj acent to the ends of the stepsin the insulating structure.

In testimonywhereof, I have hereunto subscribed my name this 23rd day ofSept,

CHARLES LE GEYT FORTESQUE. Witnesses:

HELEN BURTON, B. B. Hmns.

